Production of motor benzol



Patented Dec. 15, 1936 UNITED STATES ATENT OFFICE Clifford Banta, Englewood, N. J assignor to The Barrett Company, New York, N. Y., a corporation of New Jersey No Drawing. Application July 30, 1930, Serial No. 471,901

9 Claims.

My invention relates to the treatment of crude or unrefined benzols or crude coke oven light oil and, particularly, to the production of high grade motor fuels from crude benzols or coke oven light oil.

Crude or unrefined motor benzols are usually found to contain certain deleterious gum-forming constituents which render the unrefined or crude benzol unsuitable for use in internal combustion engines. The amount of gum present in benzol increases on standing especially on exposure to the air and the benzol becomes darkened and inferior in quality with age. The exact nature of these undesirable gum-forming constituents is not definitely known but it is believed that they are certain forms of unsaturated hydrocarbons contained in the crude benzol. In order to eliminate the gum-forming constituents of benzol it has been customary heretofore in the refining of crude benzols to remove all or substantially all of the unsaturated constituents of the-benzol by repeated washing with sulfuric acid and caustic soda.

I have found, however, that a substantial portion of the unsaturated constituents of the benzol are not gum-forming constituents and not only possess considerable fuel value but also valuable anti-knock properties.

My invention comprises a process whereby gum-forming constituents of the benzol may be selectively eliminated with but a minimum loss of other unsaturated constituents of the benzol, particularly those constituents which impart the aforementioned valuable anti-knock properties to'the' refined benzol motor fuel. I have found that the undesirable gum-forming constituents of the crude benzol may be selectively removed to a substantially complete extent with but a minimum loss of other unsaturated hydrocarbon constituents by subjecting the crude benzol to a controlled treatment with a limited amount of concentrated sulfuric acid, preferably of a strength of substantially 66 B. (93%). In accordance with my preferred procedure the crude benzol is given but a single washing treatment with a limited amount of the concentrated sulfuric acid.

The refining process may also be carried out oncoke oven light oil before the separation of motor benzol or other fractions therefrom by distillation. The removal of gum-forming constituents from coke oven light oil results in the production therefrom of distillates low in or substantially free of such constituents as in the 55 treatment of crude motor benzol. Accordingly,

the term benzol crudes as used in the appended claims is intended to include coke oven light oil as well as crude motor benzol.

The principal object of the present invention is to provide a simple and improved method of 5 treating crude motor benzols or coke oven light oil or other source of motor benzol by means of which the deleterious gum-forming constituents of the fuel are removed, the loss of valuable anti-knock constituents of the crude material 10 is reduced and a high grade motor fuel is produced.

The method of carrying out my process and the proportions, time and temperature employed in any particular case may vary somewhat depending upon the characteristics of the crude benzol treated. However, in general I prefer to use concentrated sulfuric acid of about 66 B. (93%) strength and at least of 64 B. strength (85.6% H2804), The amount of acid employed is somewhat in excess of that required to dehydrate crude benzol and is preferably about .05 lb. of 66 B. sulfuric acid per gallon of benzol in excess of that required for dehydration. Thus, inasmuch as about .03 lb. of 66 B. sulfuric acid is generally required for dehydrating the oil, the total amount of 66 B. sulfuric acid employed may vary from about .08 to .13 pound per gallon of crude benzol. In my experiments the temperature at which the reaction has been carried out has varied from room temperature or about 20 C. up to 40 C., theheat being produced by the reaction. The treatment consists in thoroughly agitating the crude benzol with the concentrated acid for a substantial time. Good results may be obtained with agitation for about 45 minutes to one hour; the length of time required depends, however, largely on the apparatus used. Under favorable conditions the time required may be considerably reduced. After treatment the acid sludge is separated and the refined motor fuel is neutralized with caustic soda, washed with Water and distilled. 1 7

In grading refined motor fuel, the degree of completeness of the acid washing operation is determined by the wash test. The details of this test are described by Weiss, Ind. Eng. Chem. vol 10, page 1008 (1918). In this method of determinationthe color of the acid layer, after being used for the wash test, is compared with standard colors designated by numbers from 0 to 14, or in a second series by numbers from C-1 to C10. The color No. 14 in the former series corresponds to C-'7 in the second series. Thus the color of the acid used in testing motor fuel is said to vary progressively from No. 0 to No. 14, C8, C-9 and C--l0 in varying from water white through yellow to brown.

While the wash test may be used as an indication of the unsaturated constituents present in benzol, the test does not indicate the presence or amount of gum-forming constituents as distinguished from other unsaturated constituents of benzol. However this test is generally prescribed in specifications for benzol to be used as motor fuel. In recent years it has been recog nized that not all of the unsaturated constituents of benzol necessarily cause gum formation and that unsaturated constituents other than the gum-forming constituents, like benzol itself, have valuable fuel and anti-knock properties. Thus I have found that benzol which may give a dark wash test, for example up to C10, may nevertheless have a content of gum-forming constituents within the limits satisfactory for use in internal combustion engines, for example .010 gram of gum per 100 cc. of benzol. Further, with the exception of the gum-forming constituents, the benzol consists entirely of constituents having valuable fuel and anti-knock properties. In recognition of this fact, there has been a recent tendency to disregard the wash test in speci fications for motor benzol and to substitute therefor a test for gum-forming constituents such as the copper dish test which is well known throughout the industry.

I have found that sulfuric acid, when used in small amounts, acts selectively upon the gum forming constituents of benzol crudes. In fact, it appears that the use of an amount of sulfuric acid in excess of that necessary to reduce the gum-forming constituents to within the limits satisfactory for use in internal combustion engines, effects a negligible further reduction in the amount of gum-forming constituents in the ben- 201 but results in a very marked reduction in the amount of valuable unsaturated constituents other than the gum-forming constituents of the benzol treated. In order to obtain the advantages of my invention, I therefore employ an amount of sulfuric acid sufficient to react selectively with gum-forming constituents to convert the same into a form separable from the benzol but insuificient to convert substantially all or more than a minimum proportion of the unsaturated constituents other than the gum-forming constituents of the benzol into a separable form.

The refining of crude benzol by my process also reduces the sulfur content and the corrosive action of the benzol. The corrosive properties of the motor benzol as given below under the heading copper corrosion have been determined by immersing a strip of polished copper in a flask containing the benzol and provided with a reflux condenser. The fiask is then heated on a water bath just gently boiling. After heating on the water bath for 30 minutes the copper strip is removed and its condition recorded.

In order that my invention shall be more clearly understood, it will be described by way of example as carried out in the treatment of crude benzol. 3000 gallons of crude benzol are agitated with about .08 pounds per gallon of 66 B. sulfuric acid for about hour. During the agitation the temperature of the mixture increases from room temperature to about 40 C. After agitation the acid sludgeis separated and the refined benzol is washed with caustic soda until neutral and thereafter washed with water and distilled. The resulting refined benzol constitutes 92.7% by volume of the crude benzol. The crude and treated benzol in a typical instance tested as follows:

Crude Treated Slight tarnish, no irridescence Start 81, dry 151 C.

Distillation The gum content of the treated benzol on storage was as follows:

Days Grams per 100 cc.

These figures are Within the range of experimental error and, therefore, it is considered that the treated benzol shows no increase in the gum content when stored for a period up to 150 days. Furthermore, motor fuels containing an amount of gum not exceeding 0.010 gram per cc. show no appreciable detrimental effects when used so that the amount of gum present in my refined produce is negligible.

In the usual acid wash process the loss of material in the acid sludge constitutes from 11 to 12% of crude material whereas the loss resulting by the use of my process ordinarily amounts to only about 7%. It is clear, therefore, that the loss of material when treating the crude benzol by my improved process is considerably less than that resulting from the ordinary acid wash of crude light motor fuels to remove the unsaturated compounds therefrom.

My process shows a considerable saving in fuel loss over alternative processes for treating crude light motor fuels to remove gum-forming constituents therefrom, as well as a saving in sulfuric acid consumption, a saving in the time required for processing the crude benzol, and a saving in the size and cost of apparatus used.

The foregoing example is illustrative of my process and is not intended as limiting the invention to the specific example, since the conditions and method of treatment may be varied materially without departing from the invention as defined by the claims.

I claim:

1. In the method of refining benzol crudes containing water the step which comprises agitating the crudes with an amount of 66 B. sulfuric acid not exceeding about 0.13 pound per gallon of the crudes but exceeding that required to dehydrate crudes.

2. In the method of refining benzol crudes the step which comprises agitating the crudes with about 0.08 pound of 66 B. sulfuric acid per gallon of the crudes.

3. The process of removing the gum-forming constituents from crude benzol which comprises subjecting the crude benzol to a single acid washing operation with about 0.08 pound of 66 B. sulfuric acid per gallon of crude benzol, separating the refined benzol from the resulting acid sludge, neutralizing and distilling the refined benzol.

4. In the method of removing gum-forming constituents from benzol crudes containing water the step which comprises agitating the crudes with concentrated sulfuric acid of at least 64 Baum in an amount greater than that necessary to dehy- =7 drate the crudes, sufiicient to remove gum-forming constituents but insufficient to remove substantially all of the unsaturated constituents of the crudes.

5. The method of refining crude benzol which comprises agitating the crude benzol containing water with sulfuric acid of at least 64 B. strength in an amount greater than that required to dehydrate the crude benzol but insufficient to remove all of the unsaturated constituents of the crude benzol until the gum-forming constituents of the purified benzol are reduced to less than 0.010 gram per 100 cc., separating the refined benzol from the resulting acid sludge, neutralizing and distilling the refined benzol.

6. In the method of refining benzol crudes the step which comprises agitating the crudes with about 0.05 pound of 66 B-. sulfuric acid per gallon of crudes in excess of that required to dehydrate the crudes.

7. The method of refining benzol crudes which comprises agitating the crudes with about 0.03 pound of 66 B. sulfuric acid per gallon of crudes while maintaining the temperature of the crudes below about 40 C., separating the refined benzol from the resulting acid sludge, neutralizing and distilling the refined benzol.

8 ."I'he method of refining crude benzol which comprises the step of agitating the crude material for a period of about one hour with about 0.08 pound of 66 B. sulfuric acid per gallon of crude benzol.

9. The method of removing gum-forming constituents from crude benzol which comprises agitating the crude benzol for about hour with about 0.08 pound of 66 B. sulfuric acid per gallon of crude benzol while maintaining the temperature below about 40 C., separating the refined benzol from the resulting acid sludge, neutralizing and distilling the refined benzol.

CLIFFORD BAN TA.

DISCLAIMER 2,064,455.-0lifl0rd Banta, Englewood, N. J. PRODUCTION OF MOTOR BENZOL.

Patent dated December 15, 1936. Disclaimer filed January 4, 1940, by the inventor; the assignee, The Barrett Company, consenting.

Hereby enters this disclaimer to claims 2 and 8.

[Ofiicz'al Gazette January 30, 1.940.] 

